Nice features, low price
Have you ever wanted one of those fine (and expensive) power supplies that you can’t buy for less than 300 bucks? Ever planned making one “made by yourself”? With digital current limiter? And if possible, for less than 50$? You’re in the right place: keep reading.
This amazing DIY Digitally Controlled PSU is the product of several months struggling with finding the better, nicest, and cheapest way of creating such a thing.
Some pictures of the final result
Have a quick glimpse at the following pictures:
Objectives & requirements (PSU Specs)
The goals and requirements I set when I was defining the project were the following:
- Build a functional PSU with two independent, floating channels
- The PSU shall have at least one clock generator
- The PSU shall have one adjustable PWM output
- Channels must be able to be switched ON and OFF
- The DC voltage range shall go from 0 to 25 Volts
- The maximum output current has to be, at least, 2 amps.
- The cost shall be lower than 70$ USD
- No series diode at the output stage
- Digitally controlled current limiter to avoid blowing things up
- USB connection to allow computer control
- A nice (and cheap) TFT Screen, with rotary encoders and a fine interface
- A lot of blinking LEDs
Wow, that sounds funny, and nearly impossible… Just that it’s not! Sit back, relax, and read on.
Circuits and arrangements we’re gonna be using
Make sure to understand the following basic PSU circuits before going any further:
- Darlington pair
- Voltage tracking loop (analog)
- Current sensing and limiting loop (analog)
- Arduino Mega (might replace it by an ESP32)
- External ADC IC